Using imaging technologies in experimental geotechnics

Digital image processing has proven to be a useful tool in analyzing experiments on geotechnical problems. The technique has been applied as a method for measuring the deformation of soil samples on-line in a small geotechnical centrifuge. The advantage of the method is that only a video camera is required as sensor and that, unlike mechanical sensors, light does not influence the behaviour of the soil. It soon appeared that there were many more applications for this measuring method in geotechnics. In the laboratory the method is used to measure deformation parameters in soil testing devices, and to monitor the transport of contaminants. In the field the method is applied to measure the surface deformation of a dike during water infiltration, which can for example be caused by wave overtopping. A more advanced application of imaging technology on granular material can be achieved by using doubly refractive grains. With this technique it is possible to obtain information about the stress distribution in the interior of the model. By using digital image processing techniques it is possible to apply this method in a geotechnical centrifuge.